From: Anders Carlsson <andersca@mac.com>
Date: Sun, 8 Feb 2009 07:46:24 +0000 (+0000)
Subject: More cleanup stack work, PopCleanupBlock now returns a struct with the switch block... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bb66f9f2e454135b86462d121629275b6ac38e96;p=clang

More cleanup stack work, PopCleanupBlock now returns a struct with the switch block and end block.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64072 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 2ab73648df..b62499d3ad 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -531,10 +531,20 @@ void CodeGenFunction::EmitCleanupBlocks(size_t OldCleanupStackSize)
     EmitCleanupBlock();
 }
 
-void CodeGenFunction::FixupBranches(llvm::BasicBlock *CleanupBlock,
-                                    const BlockVector& Blocks,
-                                    BranchFixupsVector& BranchFixups)
+CodeGenFunction::CleanupBlockInfo CodeGenFunction::PopCleanupBlock()
 {
+  CleanupEntry &CE = CleanupEntries.back();
+  
+  llvm::BasicBlock *CleanupBlock = CE.CleanupBlock;
+  
+  std::vector<llvm::BasicBlock *> Blocks;
+  std::swap(Blocks, CE.Blocks);
+  
+  std::vector<llvm::BranchInst *> BranchFixups;
+  std::swap(BranchFixups, CE.BranchFixups);
+  
+  CleanupEntries.pop_back();
+
   if (!CleanupEntries.empty()) {
     // Check if any branch fixups pointed to the scope we just popped. If so,
     // we can remove them.
@@ -558,18 +568,26 @@ void CodeGenFunction::FixupBranches(llvm::BasicBlock *CleanupBlock,
     }
   }
   
+  llvm::BasicBlock *SwitchBlock = 0;
+  llvm::BasicBlock *EndBlock = 0;
   if (!BranchFixups.empty()) {
-    llvm::BasicBlock *CleanupEnd = createBasicBlock("cleanup.end");
+    SwitchBlock = createBasicBlock("cleanup.switch");
+    EndBlock = createBasicBlock("cleanup.end");
     
+    llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
+
+    Builder.SetInsertPoint(SwitchBlock);
+
     llvm::Value *DestCodePtr = CreateTempAlloca(llvm::Type::Int32Ty, 
                                                 "cleanup.dst");
     llvm::Value *DestCode = Builder.CreateLoad(DestCodePtr, "tmp");
     
     // Create a switch instruction to determine where to jump next.
-    llvm::SwitchInst *SI = Builder.CreateSwitch(DestCode, CleanupEnd, 
+    llvm::SwitchInst *SI = Builder.CreateSwitch(DestCode, EndBlock, 
                                                 BranchFixups.size());
-    EmitBlock(CleanupEnd);
-    
+
+    Builder.SetInsertPoint(CurBB);
+
     for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) {
       llvm::BranchInst *BI = BranchFixups[i];
       llvm::BasicBlock *Dest = BI->getSuccessor(0);
@@ -612,34 +630,20 @@ void CodeGenFunction::FixupBranches(llvm::BasicBlock *CleanupBlock,
     
     BlockScopes.erase(Blocks[i]);
   }
-}
-
-llvm::BasicBlock *
-CodeGenFunction::PopCleanupBlock(BlockVector& Blocks,
-                                 BranchFixupsVector& BranchFixups)
-{
-  CleanupEntry &CE = CleanupEntries.back();
-  
-  llvm::BasicBlock *CleanupBlock = CE.CleanupBlock;
   
-  std::swap(Blocks, CE.Blocks);
-  std::swap(BranchFixups, CE.BranchFixups);
-  
-  CleanupEntries.pop_back();
-
-  return CleanupBlock;
+  return CleanupBlockInfo(CleanupBlock, SwitchBlock, EndBlock);
 }
 
 void CodeGenFunction::EmitCleanupBlock()
 {
-  BlockVector Blocks;
-  BranchFixupsVector BranchFixups;
+  CleanupBlockInfo Info = PopCleanupBlock();
   
-  llvm::BasicBlock *CleanupBlock = PopCleanupBlock(Blocks, BranchFixups);
+  EmitBlock(Info.CleanupBlock);
   
-  EmitBlock(CleanupBlock);
-
-  FixupBranches(CleanupBlock, Blocks, BranchFixups);
+  if (Info.SwitchBlock)
+    EmitBlock(Info.SwitchBlock);
+  if (Info.EndBlock)
+    EmitBlock(Info.EndBlock);
 }
 
 void CodeGenFunction::AddBranchFixup(llvm::BranchInst *BI)
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index fa23308176..836a36f952 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -131,6 +131,28 @@ public:
   /// PushCleanupBlock - Push a new cleanup entry on the stack and set the
   /// passed in block as the cleanup block.
   void PushCleanupBlock(llvm::BasicBlock *CleanupBlock);
+
+  /// CleanupBlockInfo - A struct representing a popped cleanup block
+  struct CleanupBlockInfo {
+    /// CleanupBlock - the cleanup block
+    llvm::BasicBlock *CleanupBlock;
+    
+    /// SwitchBlock - the block (if any) containing the switch instruction
+    /// used for jumping to the final destination.
+    llvm::BasicBlock *SwitchBlock;
+    
+    /// EndBlock - the default destination for the switch instruction.
+    llvm::BasicBlock *EndBlock;
+    
+    CleanupBlockInfo(llvm::BasicBlock *cb, llvm::BasicBlock *sb, 
+                     llvm::BasicBlock *eb)
+      : CleanupBlock(cb), SwitchBlock(sb), EndBlock(eb) {}
+  };
+
+  /// PopCleanupBlock - Will pop the cleanup entry on the stack, process all
+  /// branch fixups and return a block info struct with the switch block and
+  /// end block.
+  CleanupBlockInfo PopCleanupBlock();
   
   /// CleanupScope - RAII object that will create a cleanup block and
   /// set the insert point to that block. When destructed, it sets the insert
@@ -249,19 +271,16 @@ private:
   /// label.
   void EmitStackUpdate(const LabelStmt &S);
 
-  typedef std::vector<llvm::BasicBlock *> BlockVector;
-  typedef std::vector<llvm::BranchInst *> BranchFixupsVector;
-  
   struct CleanupEntry {
     /// CleanupBlock - The block of code that does the actual cleanup.
     llvm::BasicBlock *CleanupBlock;
     
     /// Blocks - Basic blocks that were emitted in the current cleanup scope.
-    BlockVector Blocks;
+    std::vector<llvm::BasicBlock *> Blocks;
 
     /// BranchFixups - Branch instructions to basic blocks that haven't been
     /// inserted into the current function yet.
-    BranchFixupsVector BranchFixups;
+    std::vector<llvm::BranchInst *> BranchFixups;
 
     explicit CleanupEntry(llvm::BasicBlock *cb)
       : CleanupBlock(cb) {}
@@ -791,13 +810,6 @@ private:
   /// EmitCleanupBlock - emits a single cleanup block.
   void EmitCleanupBlock();
 
-  llvm::BasicBlock *PopCleanupBlock(BlockVector& Blocks,
-                                    BranchFixupsVector& BranchFixups);
-  
-  void FixupBranches(llvm::BasicBlock *CleanupBlock,
-                     const BlockVector& Blocks,
-                     BranchFixupsVector& BranchFixups);
-                     
   /// AddBranchFixup - adds a branch instruction to the list of fixups for the
   /// current cleanup scope.
   void AddBranchFixup(llvm::BranchInst *BI);